Enhancement of mechanical properties and wear of AA5083/316 stainless steel surface-composite developed through multi-pass friction stir processing (MPFSP)

In this investigation, the AA5083/316 stainless steel (ss) surface composite was generated by the friction stir processing (FSP) with the aim of improving the mechanical properties, the corrosion and tribological performances of the composite. The FSP process was conducted at different tool pass numbers (1-P, 2-P, and 4-P) and a constant tool rotational (900 rpm) and travel (85 mm/min) speeds. To analyze the microstructure of the samples, optical (OM) and scanning electron microscopes (SEM) were employed to characterize the scattering of the 316 stainless steel (ss) particles within the AA5083 matrix. It was found that multi-pass FSP resulted in substantial grain refinement from 7.02 to 5.89 μm and better scattering of the reinforcement in the AA5083 Al matrix. Results also indicated that the mechanical and wear properties of the composite layers were enhanced by increasing the pass number from 1-pass to 4-pass, which can be credited to the formation of finer 316 stainless steel (ss) particles appropriately dispersed in the Al substrate. Furthermore, the results depicted that the corrosion resistance of the samples is enhanced with the increase of pass number.